Stretch comparator



Filed Sept. 22. 1932 2 Shets-Sheet l INVENTOR 11 I HERMAN Kossrm BY I,

ATTORNEY May 29, 1934.

H. KOESTER STRETCH COMPARATOR Filed Sept. 22

, 1932 2 Sheets-Sheet 2 INVENTOR Haw/w KOESTf/i ATTORNEY Patented May 29, 193s I 1,960,575

UNETED STATES FATE? OFFEQE STRETCH COMPARATOR Herman Koester, Waterbury, Conn, a-ssignor to The Bristol Company, Waterbury, Conn, a corporation of Connecticut Application September 22, 1932, Serial No. 634,351

10 Claims. (Cl. 73-51) The invention relates to measuring apparatus, metal disk with smoked film surface to reduce and more particularly to devices whereby the efthe pointer friction to a minimum and to obviate fect of humidity changes upon material such as the effects of moisture upon chart material such paper, cloth, etc., may be ascertained. As is well as the usual paper employed.

understood, for certain purposes paper, for ex- As hereinbefore noted, a strip 15 of paper or 60 ample, is required to possess a minimum stretch, like material of allowable standard stretch or particularly in its application as recording charts shrinkage and a test strip 16 are prepared in the whose accuracy is proportional to the quality of required lengths, for example, from to 11' the paper in this respect. It has been the pracand of a width of approximately being cut 10 tice, therefore, to make laboratory tests in checkwith the grain of the paper running at right 65 ing the grade of the papers employed, but this inangles to the length of the strip. One end of volves a more or less laborious and time-consumeach of these strips is then anchored firmly in ing procedure. the apparatus, for example, in the respective The present invention has for an object the clamping posts 17 and 18, and the strips are" provision of a device whereby different grades brought about suitable guide rollers 19 and 2G 70 of paper or like material may readly and rapidly which are displaced from the said posts and sebe checked against a standard sample previously cured to the frame at its upper portion as shown. ascertained to meet the users requirements. The free ends of the strips, however, are designed In carrying out the invention, a standard samto be connected to a carriage member embodying 20 ple of known stretch is cut into a strip of suitable a bifurcated element 21 having longitudinal slots 75 length and width and is opposed in the novel 22 in its tines and communicated with entrance device to a similar strip of the material under slots 23. A rod 24 extends downwardly from the test, both strips being subjected in the device to tines and is guided for longitudinal movement a humidity change, that is to say to a different in suitable bearings 25 at the outer ends of up- 25 percentage of moisture than that at which the rights or standards 26 secured to the frame. 80 standard was normalized. Any difference in A spring 27, about the lower end of the rod stretch or shrinkage between the two strips is and located between one of the standards and caused to be reproduced as a differential moveadjustable nuts 28 on the rod, serves to draw the ment which is measured or indicated in any conrod and tines downwardly or toward the said 30 venient manner, and as is well understood in the posts substantially parallel to the strips. When 5. t the free ends of the strips are connected to the The nature of the invention, however, will best said carriage member as hereinafter set forth, be understood when described in connection with said strips will thus be duly tensioned by the the accompanying drawings, in which: spring 27; and the desired tension may be se- Fig. 1 is a front elevation of the novel comparcured by setting the nuts 28 accordingly. to ator device, with a portion of the recording chart To this end there is arranged to be reciprocabroken away. bly mounted in the slots 22 an arbor member Fig. 2 is a side elevation thereof on an enlarged which is also rotatable therein. This member scale and with the upper portions shown in vercomprises trunnions 30 which extend through the tical section. said slots 22 and are connected to intermediate Fig. 3 is a fragmentary plan view. knife-edge portions 31 which are offset or dis- Fig. 4 is a fragmentary vertical section, taken placed laterally from the axis of rotation of the on the line 4.-4:, Fig. 3. arbor and to equal distances therefrom. The Fig. 5 is a perspective View of the arbor meme free ends of the two strips are to be brought over 45 her. the respective knife-edges and are adapted to be Referring to the drawings, 10 designates a removably held thereto, as by means of a spring suitable backing plate or frame member for carclamp 32 snapped over the opposite sides of the rying and supporting the various elements conknife-edges (Fig. 4). stituting the novel comparator device. At the Due to the tension provided by the spring 27 50 lower portion, for example, of this frame is roupon the carriage member, said member as a tatably supported a record chart 11 upon which a whole will be drawn toward the anchored ends of record may be effected in well known manner by the strips while the free ends thereof attached to the pointer or measuring arm 12. For more rethe arbor member will also be subjected to the fined determinations, it is preferred to provide tension through contact of its trunnions with 55 the record surface upon a chart constituted as a respective tines, or rather, with the periphery of rollers 33 carried by the outer ends of the tines and which thus serve to reduce the friction upon the said trunnions and enhance rotation of the arbor. To facilitate the attachment of the free ends of the two strips to the arbor, the same is arranged to be removable from the carriage member as through the entrance slots 23; and after said ends have been properly secured by means of the clamp 32, the arbor is returned to the carriage as in passing the trunnions through the entrance slots and into engagement with the rollers 33, and one of the trunnions extending through a guide slot 34 of the back plate.

A suitable measuring element such as the pointer or recording arm 12 is secured to the other of the trunnions 30 so that any rotational movement of the arbor will be reproduced as a corresponding angular movement of the said pointer to serve as a measure of the differential effect produced by different stretching of the two strips under humidity variations. It will be understood that both strips have been seasoned to the same relative humidity and that the pointer has previously been set on some arbitrary zero line of the chart, as, for example, in the middle of the field. If both strips then stretch alike, there will, of course, be no resultant movement of the pointer; but said pointer will trace a record upon one side or the other of the zero line where the paper strips do not react similarly, and in accordance with the differential of their respective effects.

By the foregoing arrangement, determination of the grade of a paper with respect to stretch or shrinkage is facilitated after a standard has once been selected; and the floating and removable mounting of the arbor expedites the test operations and allows also of ready adjustment of the initial tension upon both the standard and the sample under test.

I claim:

1. A stretch comparator, comprising a rigid frame including a'pair of clamping posts to anchor respectively an end of each of a pair of strips of material subject to stretch under humidity changes of the surrounding atmosphere, means displaced from the posts upon said frame and over which the respective strips are adapted to pass, a carriage yieldingly secured to the frame, an arbor rotatably mounted therein, means to secure the free ends of the said strips to the arbor respectively upon opposite sides of its axis of rotation and at a distance from its axis of rotation, whereby unequal stretching of the said strips will be reproduced in an angular movement of the said arbor proportional to the differential of the stretches, and means to indicate the degree of rotation of the arbor.

2. A stretch comparator, comprising a rigid frame including a pair of clamping posts to anchor respectively one end of each of a pair of strips of material subject to stretch under humidity changes of the surrounding atmosphere, a pair of guide rollers displaced from the posts upon said frame and over which the respective strips are adapted to pass, a carriage yieldingly secured to the frame between the clamping posts and guide rollers, an arbor rotatably mounted therein, means to secure the free ends of the said strips to the arbor respectively upon opposite sides of its axis of rotation and at a distance from its axis of rotation, whereby unequal stretching of the said strips will be reproduced in an angular movement of the said arbor proportional to the diiferential of the stretches, and means to indicate the degree of rotation of the arbor.

3. A. stretch comparator, comprising a rigid frame including a pair of clamping posts to anchor respectively an end of each of a pair of strips of material subject to stretch under humidity changes of the surrounding atmosphere, means displaced from the posts upon said frame and over which the respective strips are adapted to pass, a carriage yieldingly secured to the frame and constrained to move substantially parallel to the said strips, an arbor rotatably mounted therein, means to secure the free ends of the said strips to the arbor respectively upon opposite sides of its axis of rotation and at a distance from its axis of rotation, whereby unequal stretching of the said strips will be reproduced in an angular movement of the said arbor proportional to the differential of the stretches, and means to indi cate the degree of rotation of the arbor.

4. A stretch comparator, comprising a rigid frame including a pair of clamping posts to anchor respectively an end of each of a pair of strips of material subject to stretch under humidity changes of the surrounding atmosphere, means displaced from the posts upon said frame and over which the respective strips are adapted to pass, an elongated carriage yieldingly secured to the frame, an arbor rotatably mounted in said carriage and adapted to slide therein in the direction of the longitudinal axis of said carriage, means to secure the free ends of the said strips to the arbor respectively upon opposite sides of its axis of rotation and at a distance from its axis of rotation, whereby unequal stretching of the said strips will be reproduced in an angular movement of the said arbor proportional to the differential of the stretches, and means to indicate the degree of rotation of the arbor.

5. A stretch comparator, comprising a rigid frame including a pair of clamping posts to anchor respectively an end of each of a pair of strips of material subject to stretch under humidity changes of the surrounding atmosphere, means displaced from the posts upon said frame and over which the respective strips are adapted to pass, acarriage yieldingly secured to the frame, an arbor movably mounted in said carriage, knifeedges laterally displaced therefrom upon opposite sides of the axis of rotation of said arbor and at equal distances therefrom, and means to clamp the free ends of the said strips over the corresponding knife-edges, whereby unequal stretching of the said strips will be reproduced in an angular movement of the said arbor proportional to the differential of the stretches.

6. A stretch comparator, comprising a rigid frame including a pair of clamping posts to anchor respectively an end of each of a pair of strips of material subject to stretch under humidity changes of the surrounding atmosphere, means displaced from the posts upon said frame and over which the respective strips are adapted to pass, a carriage yieldingly secured to the frame, an arbor movably mounted in said carriage, knife-edges laterally displaced therefrom upon opposite sides of the axis of rotation of said arbor and at equal distances therefrom, and removable means to clamp the free ends of the said strips over the corresponding knife-edges, whereby unequal stretching of the said strips will be reproduced in an angular movement of the said arbor proportional to the differential of the stretches.

7. A stretch comparator, comprising a rigid frame including a pair of clamping posts to anchor respectively an end of each of a pair of strips of material subject to stretch under humidity changes of the surrounding atmosphere, means displaced from the posts upon said frame and over which the respective strips are adapted to pass, a carriage embodying a bifurcated member with longitudinally slotted tines provided with entrance slots, means to mount said carriage upon the frame for movement substantially parallel to the said strips, resilient means urging said carriage in a direction to tension the strips, an arbor slidably mounted in the slots of the bifurcated member and rotatable therein, and means to secure the free ends of the said strips to the arbor respectively upon its opposite sides and at a distance from its axis of rotation, whereby unequal stretching of the said strips will be reproduced in an angular movement of the said arbor proportional to the differential of the stretches.

8. A stretch comparator, comprising a rigid frame including a pair of clamping posts to anchor respectively an end of each of a pair of strips of material subject to stretch under humidity changes of the surrounding atmosphere, means displaced from the posts upon said frame and over which the respective strips are adapted to pass, a carriage embodying a bifurcated member with longitudinally slotted tines provided with entrance slots, means to mount said carriage upon the frame for-movement substantially parallel to the said strips, resilient means urging said carriage in a direction to tension the strips, an arbor slidably mounted in the slots of the bifurcated member and rotatable therein, rollers carried by the bifurcated member to engage with the said arbor, and means to secure the free ends of the said strips to the arbor respectively upon its opposite sides and at a distance from its axis of rotation, whereby unequal stretching of the said strips will be reproduced in an angular movement of the said arbor proportional to the differential of the stretches.

9. A stretch comparator, comprising a rigid frame including a pair of clamping posts to anchor respectively an end of each of a pair of strips of material subject to stretch under humidity changes of the surrounding atmosphere, means displaced from the posts upon said frame and over which the respective strips are adapted to pass, a carriage yieldingly secured to the frame, an arbor rotatably mounted therein, a measuring arm connected with the arbor, and means to secure the free ends of the said strips to the arbor respectively upon its opposite sides and at a distance from its axis of rotation, whereby unequal stretching of the said strips will be reproduced in an angular movement of the said arbor proportional to the differential of the stretches.

10. Apparatus of the nature set forth, comprising means to secure at one end a pair of strips of material subject to stretch under humidity changes of the surrounding atmosphere, a movably mounted carriage having an element mounted for angular movement therein and to which the opposite ends of the strips are adapted to be secured at separated points, resilient means urging the carriage in a direction to tension the attached strips, and means associated with the carriage for reproducing the angular movement of the carriage element resulting from differential stretch of the strips.

HERMAN KOESTER. 

